The present invention relates to a recoil starter adapted for use in an internal combustion engine, and in particular, to a recoil starter provided with improved unidirectional rotating means for recoiling (which hereinafter will be referred to as recoiling unidirectional rotating means) designed to transmit the rotation of a rope reel to a driven member.
A recoil starter adapted for use in an internal combustion engine is conventionally provided with a driving member having a rope reel, around which a recoil rope is wound, and a driven (idler) unit comprising a centrifugal ratchet mechanism. In order to start the internal combustion engine, the recoil rope (recoil handle) is pulled to revolve the rope reel, and the resulting revolution of the rope reel is transmitted via the driven member to the crankshaft of the internal combustion engine, to thereby start the engine.
The driving member also includes, in addition to the aforementioned rope reel, a spiral spring for recoiling as recoiling urging means for reversibly rotating the rope reel so as to wind the recoil rope, recoiling unidirectional rotating means for transmitting the rotation of the rope reel to the driven member, and an interlocking rotor.
In the conventional recoil starter, unidirectional rotating means generally includes a ratchet mechanism having one or more oscillating locking claws (ratchet claws), which are swingably supported by either one of the rope reel and the interlocking rotor, an urging member for urging the oscillating locking claw to move radially, and one or more engaging claws, which are attached to the other of the rope reel and the interlocking rotor. When the rope reel is rotated in the driving direction by pulling the recoil rope so as to start the internal combustion engine, the oscillating locking claws are caused to contact and engage with the engaging claws, thereby transmitting the rotation of the rope reel to the interlocking rotor.
Conversely, when the rope reel is permitted to rotate reversibly to the aforementioned driving direction by the effect of the spiral spring for recoiling after the engine is started and the recoil rope is released, the oscillating locking claws and the engaging claws are released from their engagement, whereby the rope reel and the interlocking rotor are permitted to independently rotate in the directions opposite to each other.
The recoiling unidirectional rotating means that has been mounted on this conventional recoil starter described above is constructed such that the oscillating locking claws (ratchet claws) and the engaging claws are permitted to engage with or disengage from each other via the swinging movement, in radial direction, of the oscillating locking claws, so that if a plurality of oscillating locking claws are to be mounted on the ratchet mechanism in order to enhance the reliability of power transmission, all of the oscillating locking claws are required to be independently supported swingably, and at the same time, an urging member is required to be separately attached to each of the oscillating locking claws.
As a result, the conventional recoil starter suffers from a drawback in that a large number of parts are required to be employed, its structure is complicated, it requires troublesome assembling and attachment work, and the manufacturing costs are relatively high.
Accordingly, there exists a need in the art for a recoil starter which can overcome the aforementioned disadvantages associated with the conventional recoil starter with unidirectional rotating means.
An object of the present invention is to provide a recoil starter having recoiling unidirectional rotating means, which is reasonably simple in structure and can be easily assembled and attached, thereby making it possible to effectively reduce the manufacturing cost of the recoil starter.
These and other objects of the invention, which will become apparent with reference to the disclosure herein, are accomplished by the recoil starter according to the present invention which fundamentally includes a driving member, which is provided with a rope reel around which a recoil rope is wound to thereby enable the rope reel to be rotated by pulling the recoil rope, recoiling urging means for reversibly rotating the rope reel to thereby wind the recoil rope, and an interlocking rotor to which the rotation of the rope reel is enabled to be transmitted, and a driven member operationally coupled to the driving member, to which the rotation of the driving member is transmitted.
The driving member further includes recoiling unidirectional rotating means operationally coupled to the interlocking rotor, the recoiling unidirectional means including a movable locking claw member which is supported by one of the rope reel and the interlocking rotor in such a manner that it is rotatable integrally therewith and movable in a direction along the rotational axis thereof, an urging member for urging the movable locking claw member toward the other of the rope reel and the interlocking rotor; and an engaging member mounted on the other of the rope reel and the interlocking rotor. The unidirectional rotating means is characterized as being constructed in such a manner that when the rope reel is rotated in the driving direction, the movable locking claw member is caused to contact and engage with the engaging member to thereby enable the rotation of the rope reel to be transmitted to the interlocking rotor, and that when the rope reel is rotated reversibly to the driving direction relative to the interlocking rotor, the engagement between the movable locking claw member and the engaging member is released.
In a preferred embodiment of the present invention, the rope reel is provided with a guiding/supporting portion for fitting therein the movable locking claw member while allowing the movable locking claw member to slide along the aforementioned rotational axis, and the engaging member being formed integrally with the interlocking rotor.
Preferably, the movable locking claw member is provided with a locking claw, which includes a locking face formed perpendicular to the rotational direction of the movable locking claw member, and an inclined face located behind the locking face in the aforementioned driving direction.
The engaging member is provided with an engaging claw having an engaging face formed perpendicular to the rotational direction of the engaging member, and an inclined face located in front of the engaging face in the aforementioned driving direction.
The movable locking claw member is provided with a couple of locking claws which are spaced apart from each other along the circumference of the rotational axis at an angle of 180 degrees.
The engaging member may be provided with eight, six, four or two of the engaging claws which are spaced apart from each other along the circumference of the rotational axis at an angle of 45 degrees, 60 degrees, 90 degrees or 180 degrees, respectively.
Buffering/power-accumulating means may also be disposed at a midway of power transmission system between the driving member and the driven member.
The buffering/power-accumulating means is enabled, during the driving process by the driving member, to accumulate the power supplied by the driving process while alleviating any impact to be imposed by the driven member, the accumulated power being subsequently employed for driving the driven member.
Preferably, the buffering/power-accumulating means includes a spiral spring mechanism and is preferably provided with unidirectional rotating means for enabling the interlocking rotor to rotate only in the driving direction.
The recoil starter according to a preferred embodiment of the present invention which is constructed as previously described can be operated as follows. When the recoil rope is pulled to revolve the rope reel in the driving direction so as to start the engine, recoil urging means (spiral spring) is wound and, at the same time, the movable locking claw member which is slidably fitted in the guiding/supporting portion of the rope reel is also caused to rotate. In this case, since the movable locking claw member is being urged to move toward the interlocking rotor by urging means such as a coil spring, the locking face of the locking claw is permitted to contact and engage with the engaging face of the engaging claw of the engaging member, which is mounted on the interlocking rotor, immediately after the initiation of the rope-pulling operation (starting operation), thereby enabling the rotation of the rope reel to be transmitted to the interlocking rotor. As a result, the rope reel is permitted to rotate together with the interlocking rotor in the same direction, this rotation being successively transmitted via the driven member to the crankshaft of the internal combustion engine to thereby achieve the start-up of the engine.
Once the engine has been started, the recoil rope is released and the rope reel is forced to rotate reversibly to the driving direction by the effect of the recoiling urging means so as to rewind the recoil rope. At this moment, the inclined face of the locking claw of the movable locking claw member can not be engaged with the inclined face of the engaging claw of the engaging member even though these inclined faces are permitted to slidably contact each other. As a result, while permitting the engaging claw to successively pass over the locking claws, the movable locking claw member (the locking claws) is caused to move toward the rope reel against the urging force of the urging member, thereby permitting the engaging claw to disengage from the locking claw, whereby the rope reel and the interlocking rotor are permitted to individually rotate in the directions opposite to each other.
As explained above, since recoiling unidirectional rotating means, which is mounted on the recoil starter of the present invention, is constructed such that the engagement and disengagement between the locking claws and the engaging claws can be executed by moving the movable locking claw member provided with the locking claws in the direction along the rotational axis, a plurality of locking claws are no longer required to be supported in a manner that each of the locking claws is enabled to individually oscillate as seen in the case of the conventional ratchet mechanism provided with oscillating locking claws. Moreover, the movable locking claw member is only required to be urged to move toward the interlocking rotor by making use of a single urging member. The locking claws, therefore, are no longer required to be separately provided with an individual urging member. As a result, it is now possible to reduce the number of parts to be employed, to simplify the structure of the recoil starter, and to easily assemble and attach the recoil starter, thus making it possible to effectively reduce the manufacturing cost thereof.
Furthermore, since buffering/power-accumulating means, which includes, e.g., a spiral spring mechanism, is interposed at a midway of the power transmitting system between the driving member and the driven member, it is possible to minimize fluctuation in the rope-pulling force so as to allow for a smooth rope-pulling operation, thus enabling even a person having weak physical strength to easily start the engine.